1. Field of the Invention
This invention relates to an air cushion vehicle of the skirted type with a composite hull which includes an inflatable to provide buoyancy and which surrounds a hard structure, wherein the propulsion, seating and controls are contained. The skirt system provides a balanced flow of air around the perimeter of the vehicle to prevent rapid cushion decay which may result in "plough in" of the vehicle.
1. Description of the Prior Art
Considerable development work has been done in the field of air cushion vehicles, which are more popularly known as hovercraft. Many of such craft are designed to be used both on land and water.
Examples of prior art structures are shown in the U.S. patents to Bliss U.S. Pat. No. 3,420,330; Cockerell U.S. Pat. No. 3,424,266; Beardsley U.S. Pat. No. 3,429,395; Clarke U.S. Pat. No. 3,444,952; Schneider U.S. Pat. No. 3,970,121; and the British patents to Winter No. 1,176,642; Latimer-Needham No. 1,245,454; Welfare No. 1,275,053; Riddle No. 1,306,687; Paoli No. 1,381,806; and Peissel et al. No. 1,479,315.
When using air cushion vehicles on water, and particularly with smaller craft when moving at speed across water they will operate satisfactorily if the flow of air into the cushion is maintained. If the vehicle moves downwind, the drag, and therefore the thrust required to maintain speed, decreases. Under certain conditions the volume of air fed into the cushion may decrease. If this reduction allows the cushion to decay the craft will "plough in", and cause the occupants to be thrown in the direction of the "plough-in" with possible resultant injury to the vehicle and its occupants.
None of the prior art structures provides an effective solution to the ploughing tendencies of air cushion vehicles resulting from the decay of the air cushion, and particularly where this occurs at the bow of the vehicle.
In order to overcome the "plough-in" tendency a skirt system was developed which prevents "plough-in". The system provides a balance between the volume of air fed into the cushion, and the amount fed to the individual segments comprising the skirt that forms a seal around the cushion and is satisfactory whether the vehicle operates on land or water.
The vehicle can be provided with a ballast system for trim and also provides additional positive advantages not found in the prior art structures.